This invention relates to a staple gun and will have specific reference to a staple gun for attaching tabs or labels to wood products and the like.
It is becoming common place for lumber companies and mills to use labels bearing bar codes, commonly referred to as UPC labels, for inventory control and computer pricing. Previously such labels were attached by a user carrying a roll of the UPC labels placing one against the board, stapling it to the board and then severing the stapled label from the remainder of the roll. This process, when performed by hand, is very time consuming which increases the price of lumber to the consumer.
Lumber is often shipped great distances and stored in harsh environmental conditions for extended periods of time. In particular, the lumber may be left on sea docks or in open lumberyards for months at a time. During these periods the lumber is subject to harsh environmental conditions such as rain, snow and high winds, and other conditions such as pollution and bird droppings. During transit on trains or on open semi-tractor trailers, the lumber units may be subjected to flying debris such as small sticks and stones, which may hit the lumber at speeds of seventy miles an hour. Due to the high cost of lumber, and in order to minimize the damage done to the lumber during transport and storage, it is desirable to protect the lumber from exposure to these harsh environmental conditions.
Lumber units, which are shipped in a variety of sizes, typically are wrapped in a protective covering, such as Nova-Thene Plus TP (Trademark owned by Intertape Polymer Group of Nova Scotia, Canada), a high strength, lightweight coated fabric consisting of a reinforcing high density polyethylene scrim coated on both sides with a film of low density polyethylene blended with other specialty resins. The protective covering typically is secured to the lumber unit by fasteners such as staples that are shot from a staple gun through the covering and into the lumber. The staple typically retains the sheeting on the lumber unit during transport and storage but must be removed prior to sale or use of the lumber.
When covered lumber unit is subjected to high winds, the high winds may tend to tear the protective covering from the lumber unit due to the small surface area of the staple in contact with the cover. In other words, as the covering is pulled from the lumber, the staples tend to tear through the cover (termed staple “pull through”). Moreover, during purposeful removal of the covering from the lumber prior to use, pulling of the covering from the lumber tends to result in the staple tearing through the cover such that the staples remain in the lumber. When staples remain in the lumber, the staples may damage or destroy saw blades used to cut the lumber. Partially removed staples with a single leg remaining in the product (“leg-out” condition) are also hazardous to personnel who may be injured from the protruding staple leg. In addition, staples left remaining in the lumber mar the appearance of the lumber and decrease the value of expensive specialty lumbers.
One solution is to secure the protective cover to the lumber by use of a polymeric tab, stapled through the covering into the product. Tabs are used to distribute strain on the protective covering. This reduces staple pull throughs providing for a stronger and more durable covering. The tabs can be imprinted with the company's trademark, safety designation, product information, etc. During purposeful removal of the cover, the tabs and staples normally come free. Experience has shown that 95% to 100% of the staples will be thus removed when tabs are used.
Presently the tabs are separately positioned and stapled. This results in higher labor expenditures and requires two-handed operation. Because the protective covering must also be held in position during the stapling process, two workers are typically required (first worker holds the covering in place, second worker positions and staples tab).
When only a single worker is available, the awkwardness of affixing a tab is quickly apparent. First the covering is brought into position and a tab positioned. The worker uses one hand to both hold the tab in position as well as holding the covering in position then uses the other hand to operate the staple gun. This awkwardness leads to many poorly covered products as either the covering or tab slips before the staple is driven. Worker injuries also occur when staple guns are engaged prematurely or staples penetrate into the hand holding the tab in position.
It is therefore desirable to reduce the labor requirements, injuries and awkwardness of affixing tabs and labels to lumber and products covered with protective coverings.